Energy efficiency measurement

Energy efficiency measurement[1]

The purpose of the practical work is to measure ULPMark-CoreMark at 24 MHz frequency. The following tools are required to complete the work:

  • CubeMonitor Power - software that can be downloaded from the manufacturer’s website;
  • STM32CubeIDE - development environment, which can also be downloaded from the ST website;
  • firmware files for testing at 01_CoreMark_24MHz.bin;
  • debug board STM32L562E-DK, which will be used remotely thanks to access via the All-Hardware service;
  • the operating system for the development environment is Windows, since the service configuration program is Windows only.

The sequence of practical work is as follows:

  1. Go to the All-Hardware website and book STM32L562E Discovery board.
  2. On the local computer, open a command prompt window and go to the following folder (the full path depends on the installation location of the STM32CubeIDE environment):
    D:\ST\STM32CubeIDE_1.5.1\STM32CubeIDE\plugins\com.st.stm32cube.ide.mcu.externaltools.gnu-tools-for-stm32.7-2018-q2-update.win32_1.5.0.202011040924\tools\bin
  3. Create files with *.elf extension based on existing files with *.bin extension:
  • arm-none-eabi-objcopy –I binary –O elf32-littlearm –change-section-address=.data=0x8000000 –B arm –S “d:\compel\energy_efficiency\bins\01_CoreMark_24MHz.bin” app24.elf
  • arm-none-eabi-objcopy –I binary –O elf32-littlearm –change-section-address=.data=0x8000000 –B arm –S “d:\compel\energy_efficiency\bins\01_CoreMark_110MHz.bin” app110.elf
  1. Launch GDB:
    arm-none-eabi-gdb.exe
  2. Connect to the remote server:
    target remote IP-address: Port
    The IP-address and Port parameters are taken from the All-HW service settings, page “Connection and Tools” (see Figure 1).

  1. Download and start the application:
    load app24.elf
    mon reset 0
    quit
    Figure 2 shows the EEMBC measurement results, which will serve as a reference for the test.

To run the tests, you need to install software for emulating the COM port. To do this, after opening a debug session, follow the links on the “Connection and Tools” page in the “Virtual COM port configuration” section (see fig. 3).

_3

First, follow the link “Download Virtual COM port application”, download and install the All-Hardware-Setup.exe application with administrator rights.

After installing the program, the message shown in Figure 4 appears.

_4

Then follow the link “Download Virtual COM port configuration file” to download the configuration file then run it using the application installed earlier. To run the configuration file, select “Open” in the All-Hardware-Setup.exe program (see fig. 5).

_5

After that, a new COM port should appear in the device manager, through which application data will be exchanged on the local computer with the remote board. To connect via a COM port, you can use the terminal available in the “Terminal” tab of an active session (see fig. 6).

After opening the virtual COM port, launch the Power Monitor application. In the “Select device” menu, select the required COM port and press the “TAKE CONTROL” button (see fig. 7).

_7

After that, you need to setup the configuration in the Power Monitor program in the correct order (see fig. 8).

After pressing the “Show Report” button, the window shown in F igure 9 appears.

Figure 9 shows the measurement results at 24 MHz. Using the data shown, we can calculate the ULPMark-CM (formula 1):

__1

According to data from the official website of EEMBC, we get ULPMark-CM = 18.4. Thus, the result of practical measurement using the remote debugging service is very close to the official result of EEMBC.

Energy efficiency evaluation is very important for embedded systems based on microcontrollers, especially for those operating in standalone mode. EEMBC tests allow you to accurately estimate the power consumption of the device, taking into account all possible power saving modes. Since these tests are unified, they allow you to select the most suitable device.

The ALL-HW service allows you to evaluate the parameters of the device without having to purchase this device. This hands-on exercise showed that the results obtained using the remote debug board from ALL-HW are very close to the official EMBC results.

STM32L5 controllers show good results and can be applied for power-critical applications. The presence of services such as EEMBC and ALL-HW allows the most accurate assessment of the main performance characteristics of the device, such as performance and power consumption.

References:


[1] Alexey G. (5th February 2021). Secrets of STM32L5 Power Consumption Evaluation, https://www.compel.ru